Cargo aircraft typically have a center of gravity (CG) that is typically forward of the main landing gear. There may thus be a tendency during loading/unloading applications for those aircraft equipped with rear cargo ramps for the aircraft to shift about the main landing gear assembly which in turn raises the aircraft nose. In extreme situations, aircraft shifting during loading/unloading could cause a severe tail strike damaging the airframe and/or exposing personnel to injury hazard. For these reasons, it is advisable for cargo aircraft to include additional tail ground-stabilization aft of the main landing gear during loading/unloading operations.
A variety of aircraft tail stabilization assemblies are generally known. For example, tail stabilization assemblies are known which are positionally fixed and consist of a fixed support that is typically associated with ground-based equipment manually placed under the aircraft. As can be appreciated such fixed stabilization assemblies require the pre-positioning of the ground based equipment as well as a substantial time to install thereby prolonging the loading/unloading operation, each being an obvious disadvantage if the cargo aircraft is being loaded/unloaded in an active combat zone.
On-board stabilization systems which may be mechanically or manually operated are also known. For example telescopic strut stabilization systems are know that usually employ on-board hydraulic and/or electric actuators. Telescopic strut stabilization systems typically include a main strut and a retraction actuator as the same component.
An on-board tail jack assembly is also known from U.S. Pat. No. 4,593,871, the entire content of which is expressly incorporated hereinto by reference, which includes a manually activated hydraulic jack system and a strut that may be operatively fixed to the jack system. The operator may thus extend/retract the strut as may be needed to stabilize the tail. However, when not in use, the strut must be physically disconnected from the jack and stored remotely (e.g., as part of the tail stairwell).
Retractable strut stabilization systems are also know which employ hydraulic and/or electric actuators so as to be capable of deployment between a stowed condition within a strut bay of the aircraft fuselage and an extended condition whereby the strut stabilizes the aircraft tail. Such retractable stabilization systems will typically be equipped with a strut door which can be manually operated or actuated by a mechanism linked to the stabilizer or by a dedicated door actuator.
Retractable strut stabilization systems however are problematic to operate in the event that the strut is not aligned with the strut bay during retraction. That is, when a retractable strut stabilization system is deployed during an aircraft loading/unloading operation, side loads can be experienced which can cause the strut to become off-centered or misaligned with the strut bay. If the strut is then attempted to be retracted into the strut bay while off-centered or misaligned, it could become jammed thereby precluding operation of the aircraft.
What has been needed in the art, therefore, are retractable strut assemblies that have a self-aligning mechanism to address the problems associated with the strut being off-centered or misaligned as a result of the aircraft loading/unloading operations. As such, a self-alignable retractable strut assembly would provide a measure of safety and reliability for the cargo aircraft operations. It is towards fulfilling such needs that the embodiments of the invention herein are directed.